The present invention relates to a method and apparatus for pitting peaches, especially cling peaches.
Most methods and machines previously known for this purpose generally have utilized blades or cutters to separate the stone from the fruit pulp or flesh. Other known methods and machines do not use blades or cutters and rely on causing relative rotary movement between the stone and the pulp to produce their separation, although the means for securing the pulp and causing its rotation are deffective and inefficient. The efficiency of a peach pitting operation is judged mainly from a time standpoint and amount of fruit recovered. These factors are of paramount importance. The principle objective of the present invention is to provide a unique method and apparatus that will efficiently recover the greatest amount of fruit in the least possible time. The present invention differs from the prior art for many reasons which will become evident as the description of the present invention unfolds and among which are its continuous operation and its use of a novel elastic, fruit-gripping and rotating means.
Some of the most outstanding advantages of the present invention are the following:
A. Better presentation and appearance of the stone-free fruit halves, due to the separation of the stone from the pulp without the intervention of pulp deteriorating elements or tools, whereby it is possible to vary the force with which the fruit is "held" and thus, adapt the invention to different types of peaches, such as those of the clingstone or free-stone types, as well as, to fruit of different degrees of ripeness;
B. Minimum loss of pulp regardless of its shape or size of the stone;
C. Less possibility of obstruction and longer uninterrupted operation; and
D. Lower maintenance costs due to the reduction in the number of moving mechanical parts and to the lack of complex mechanisms.
In accordance with the present invention a peach to be pitted is presented to the apparatus oriented in such manner that its line of separation between its halves is in alignment with two coplanar mounted sharp metallic plates. The plates engage the subject peach and give it a diametrical cut to a depth reaching nearly to the stone and then completely up to the stone whereupon the plates grasp the stone and hold it securely during the ensuing pitting operation. The next step is to simultaneously and uniformly grasp about two-thirds of the external semi-spherical area of each half and then rotate the two halves, for example 180.degree. about their own axis, in opposite directions, maintaining the stone centered and stationary between the metal plates. The grasping of each half of the fruit is achieved by means of the novel elastic gripping means of the present invention and comprises a diaphragm adapted to contact, due to the effect of a fluid acting thereon, a fruit half with a force sufficient to transmit a rotation to the fruit.
As the two halves rotate, and because the stone is firmly held between the two plates, the pulp around it separates from the stone due principally to the different consistency between the wood of the stone and the soft tissues of the pulp, with the separation being effected with minimum tearing of the pulp in its zone of adhesion to the stone. This result is achieved by the combined effect of the rotation and the favorable pressure distribution, generally uniform, applied over the external surface of each half, (regardless of its profile) by the elastic gripping means.
Following this, the two de-stoned or pitted halves are freed, by disengaging the gripping means and the stone is freed by separating the metal plates.
This complete operation as described above is effected by means of a unique combination of mechanical movements operated by a pneumatic or hydraulic system conceived for this machine, and the operation can be continuous, using an automatic feeder or manual feeding.
In the preferred embodiment, the apparatus consists of a rotating plate on which are defined four stations. As each station passes by a feeding station, it receives a peach which is split and de-stoned and afterwards discharged at a discharge station. The inventive combination allows continuous operation, with its consequential advantages. More specifically, the preferred machine consists of a central rotor incorporating a plate with two pairs of diametrically opposed operating stations, determined by eight sectors, four of which are fixed to the plate and four movable with respect thereto with an angular, coplanar movement, thus determining the variation of the aperture of said operating stations. Furthermore, two lateral supports are provided, one on each side of the plate, carrying four pairs of elastic gripping devices, each pair of which is made to move simultaneously and in opposite directions with alternative linear movement oriented perpendicularly to the plate and coinciding with a preselected indexing relative to one of the operating stations. As the elastic gripping devices reaching their closest approach to the plate, a compressed fluid, such as air, simultaneously enters an interior chamber of each gripping device, by means of a charge-discharge valve incorporated into the body of the same, causing the elastic and concave zone of the front wall of the gripping device to deform outwardly, adapting itself with sufficient force to the external surface of the peach half. This deformed condition is maintained during a portion of the rotation of the gripping devices about the common equidistant axis of rotation of the plate and during which both gripping devices rotate approximately 2/3 of a complete turn in opposite directions about their own central axis of rotation. Subsequently, the compressed air is discharged by means of the same valve and the gripping devices are caused to separate, whereby the peaches halves are freed and discharged. The stone or pit is transported to the stone discharge zone where it is freed by the operation station, which is opened, and consequently the stone falls out by gravity or is extracted by a rotary fork synchronized with the plate rotation. This fork sweeps both sides the sectors defining the operating station. Rotation of the plate continues into the loading zone in which a fruit loading device, synchronized with the passage of each operating station, describes an arched to and fro trajectory or path, in such a manner that one of the dead ends of its path coincides with the trajectory or path of said operating stations.
It is obvious that the number of operating stations defined on the plate, as well as the number of sectors and the number of elastic gripping devices, may be varied without departing from the fundamental features of the present invention, such variation principally aimed at changing the operative speed.